In Situ Growth and Activation of Ag/Ag2S Nanowire Clusters by H2S Plasma Treatment for Promoted Electrocatalytic CO2 Reduction

Nonmetallic activation of metal electrodes is effective and universal to improve the catalytic activity for the CO2 reduction reaction. Here, selective electrocatalytic reduction of CO2 is performed on a plasma-activated Ag/Ag2S catalyst for the first time. By a facile H2S plasma treatment on Ag foil and subsequent electrochemical prereduction, Ag/Ag2S nanowire clusters are obtained in situ with different sizes. High Faradaic efficiency for CO generation on Ag/Ag2S is shifted to a significantly lower overpotential compared with untreated Ag foil with high current density. Density functional theory studies reveal that the promoted catalytic activity can be ascribed to the enhanced CO2 activation and reduced reaction energy barrier of the limiting step.